This invention relates in general to the formation of structures by build-up welding and in particular to a new and useful method and apparatus for treating the welded structure as it is formed.
The invention relates to a process for locally cooling the surfaces of shape-welded workpieces before and/or after the weld location, using a water/air mixture.
In shape-welding of workpieces from certain metals, e.g. austenitic steels or low-alloy quenched and tempered steels, the temperature of the workpiece is kept below a certain critical level in order to obtain the desired quality grades. For this reason a part of the heat of the welding zone is often removed by cooling the workpiece behind and/or before the weld location.
In such cases cooling water is mostly sprayed under pressure on the workpiece and the steam generated is exhausted.
A known cooling device (German AS No. 29 42 868) of this type consists of a nozzle arranged in a guide funnel and trained on the workpiece, as well as a hood encircling the guide funnel and connected to an exhaust unit. As steam generated during the workpiece cooling is deleterious to welding processes, it must be removed thoroughly from the workpiece. This requires the use of a cooling device comprising elaborate and expensive equipment.